Concepts are basic elements of thought. Piaget has a conception of the nature of concepts as informational or computational operations performed in an inner milieu and enabling the child to understand the world in which it lives and acts. Concepts are, however, not merely logico?mathematical but are also conceptually linked to the mastery of language which itself involves the appropriate use of words in social and interpersonal settings. In the light of Vygotsky's work on the social and interactive nature of children's thinking and the nature of language as an essentially public currency of rule?governed signs, we are led to reconstrue conceptual mastery as the acquisition of an interactive and interpersonal repertoire of tools which introduces the child to the world of those who educate it. In this way we come to see the elements of mind as constitutively involving that activity in which the determinants of meaning constrain and direct the child's linguistic development